Gas turbine engines used for powering aircrafts comprise a combustor in which fuel is mixed with compressed air and ignited to provide combustion gases for the turbine section of the engine. In a slinger combustion system, fuel is delivered and atomized through spraying fuel through a rotary fuel slinger. The rotary fuel slinger is designed for maximum fuel flow and optimized for cruise condition to improve the combustion efficiency and thus reduce smoke and gaseous emission. Thus at low power levels, when the slinger rotates at lower speeds, fuel tends to not atomize properly, thereby resulting in low combustion efficiency, and high emission/smoke/particulates/unburned hydrocarbons.
Conventional rotary slingers have to be operated at high speed for properly atomizing the fuel. When, the slinger is rotated at low speeds, such as during starting and altitude relight conditions, the fuel atomization effect of the slinger is relatively poor, thereby requiring a relatively expensive and complex architecture for the ignition system with relatively long igniters to deliver spark energy close to the slinger system. Starting a slinger combustor at low speeds and at high altitudes without relatively complex high pressure fuel injection system has heretofore been challenging.